As mobile electronic devices, such as video cameras, mobile phones, mobile computers, become lighter and multifunctional, technologies concerning secondary batteries that are used as a power source for driving such mobile devices have been actively studied. Secondary batteries include, for example, nickel-cadmium batteries, nickel-hydrogen batteries, nickel-zinc batteries, lithium secondary batteries. Among these, lithium secondary batteries have become widely used due to their advantages, such as coming in various sizes and having a high operation voltage and high energy density.
According to Korean Patent Application Publication No. 2005-0069075, rechargeable secondary batteries are recently receiving attention as a driving power source for Electric Vehicles (EV), Hybrid Electric Vehicles (HEV), Plug-in Hybrid Electric Vehicles (P-HEV), etc. as they are considered a solution to air pollution, which is caused by existing gasoline vehicles, diesel vehicles, etc. all of which use fossil fuel. Unlike compact mobile devices, a medium- or large-sized battery module in which many battery cells are connected to each other depending on demanded output power is used for a medium- or large-sized apparatus such as a vehicle.
Conventionally, various cooling systems for dissipating heat generated by battery modules containing secondary battery cells therein have been used. Specifically, there is an air cooling system in which battery cells are stacked with a gap therebetween and an air channel is formed in the gap. The air cooling system has a disadvantage of low cooling efficiency attributable to a narrow air channel. Moreover, it is difficult to effectively and sufficiently dissipate the heat generated by battery cells because the cooling is performed using only the gap having a limited size between stacked battery cells. Therefore, operation performance or driving stability of devices that use the battery cells is dramatically deteriorated.